Fig. 2

Study of the cell-to-cell variability observed in the Snf1/Mig1 system. (a)(b) Hxt7-GFP before and following a switch from ethanol media to media containing 220 mM glucose. (a) Time lapse microscopic images, upper images show HXT7-GFP, the lower images show brightfield. (b) Fluorescence intensity along an intersection through the yeast cells. The fluorescence intensity is higher at the points the intersection line crosses the cell membrane and does not change over time. The result of only one cell is displayed but multiple cells were analyzed and none of the cells showed a decrease in membrane localization of the Hxt7 transporter after 15 min following the shift to glucose media. (c) The ratio 15 min after glucose upshift plotted over the cell size for the HXT1 strain. The cell size is plotted on the x-axes. As a measurement for the Mig1-Snf1 pathway response we chose the Mig1 nuclear/cytosolic ratio. Upshifts to higher glucose concentration; 0 to 220 mM (blue diamonds), 0 to 55 mM (red squares) and 0 to 27.5 mM glucose (green triangle) result in higher final ratio while upshifts to lower glucose concentration 0 to 11 mM glucose (purple crosses), 0 to 2.75 mM (blue stars) and 0 to 0 mM glucose (orange dots) display a lower final ratio. (d) Hxt7-GFP pregrown overnight in 3% ethanol media. Upper image shows the bright field image, lower image shows the cellular distribution of Hxt7-GFP